Process of treating bituminous compositions.



L. KIRSCHBRAUN.

PROCESS OF TREATING BITUMINOUS COMPOSITIONS,

APPLICATION FILED JUNE 18, 1914.

I 1 I a I Patented June 20, 1916.

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Specification of Letters Patent. Pwhgmtrgfl J mg 2% terry,

Application filed .Tuneltl, 19%; I Serial No. 845,798. i

Tor/ll whom it may concern:

Be it knownthat I, LESTER KmsormnAUN,

' a citizen of theYlUnited States, residing in lit Elli

the city of Chicago, county of Cook, and- State of lllinois, have invented certain new and useful lmprovements in 'Processes' of Treating Bituminous Compositions, of which the following is a specification.

This invention relates to improvements in processes of'treating bituminous composition and-fhas, among its salient objects to provide a process for regenerating old or used bituminouscompositions such as sheet asphalt pavements, asphaltic concrete pavements of analogous compositions of stone, sand, and bituminous binder; to provide an improved process of obtaining the result last mentioned in such a way as to avoid burning, overheating or otherwise injuring the bituminous or asphaltic binder of such composition; to provide a process of the character referred to in which the bituminous composition in question is regenerated by the use of superheated steam; and in general to provide an improved-process of the character referred to.

The invention consists in-the matters here-.

inafter described and more particularly pointed out in the appended claims.

lln'the' draWiDgs FiguI-e 1 is a side elevation with parts broken out and shown in section of an apparatus suitable for carrying out my invention. Fig.2 is a transverse vertical sectional view ofthe same.

As lis 'well known, asphalt pavements are practically universally used through the United States. These asphalt pavements are composed of a mixture of stone, sand, mineral powders and bituminous hinder, the proportion of the mixture varying with the character of the pavement and the condi- I tions in any particular case. Annually, millions of square yards of these pavements must be repaired or replaced because either they are worn out or because of faulty construction. One ofthechiefcauses which necessitates the replacing of or repairing of old pavementsis the hardening of the bituminous binder, which in itself generally does not exceed ten per cent. of the composition. The other ninety per cent. composes the mineral aggregate, and this is practically unchanged through any period of Heretofore, it has been necessary when time. a new pavement is to be laid, to first take up and abandon the old pavement, includ 7 art.

ing not only the bituminous binder but the mineral part'of the composition as well, and this was true despite the fact that the mineral aggregate of such old composition wasmet as good as when first Ilaid. The

difiticulty has been that heretofore no successful method has been devised or used for softening and disintegrating the pavement by heat without atthe same time injuring and destroying the'bituminous constituents of the pavement. The value of a process which would permit the reuse of'a paving composition as to its mineral composition as well as a greater part of the binder is apparent and thenecessity and advantage of such a process ,is well recognized inthe l am aware that attempts have been made to devisesuch a method but heretofore none of these methods-havebeen commercially successful. 1 By the present invention, old

paving composition is acted upon by a non o ridizing agent and insuch a way that the bitum nous binder therein is raised to a temperature above its melting point, yet be- I low that at which it will be injured, thereby allowing the paving composition to soften and disintegrate and acquire a degree of plasticity at which it may be raked and spread as a covering in the usual manner. Tf the old paving composition'contains a bituminous binder which has become much hardened through the process of time or so the binder does not possess sutlicient cement ing powers, the hot softened disintegrated composition as above, prepared may .have

added; to it during the process a suflicient amount of fresh binder to soften the meta morphosed material in the old composition.

Tn carrying out my improved process the.

old paving composition is removed and broken'up into relatively small particles.

1% be softened enough to melt the binder which the heat orifl ames of the'furnace are applied directly to the drum, the latter will become overheated and the contents of the drum injured. The fresh material may be continuously fed to the drum, the material being introduced at one end and delivered from the-other end. The temperature of thewsuperheated steam will be upward of 400 F, and may reach 700 or more. The contents of the drum however only need .to

in most cases would not be in excess of 300 F. j

' Referring now. to the apparatus'shown in the drawingsldesignates a furnace in'the upper .end of whichis supported a cylindrical drum 2. Around the lower sideof this drum 2 is arranged'a, plurality of coils.

or steam pipes 3 having an inlet branch 4i leading to the boiler" and an outlet branch 5 as shown at 6 which communicates with j the rear 0r delivery end of the drum.

These steam'pipes 3 are arranged as shown in the drawing and form in effect a protects ing wall between the. fire of the furnace and the shell of the' drum. The object of this I construction is to provide not only means for superheating the steam as it passes from the boiler to the drum,- but also to protect the drum audits contents from the direct action of the heat of the furnace. If some means were not provided. for protecting the shell of the drum against the action of the furnace, the drum would become over-heated and injure the bituminous binder of the composition which is being treated. Within thedriim is suitablymounted'a shaft 7 driven from any suitable gearing 8. On this shaft is mounted a series of conveyer blades or teeth 9 which are or may be similar in construction to the teeth of a pugmill mixer used in mixing asphalt. The material is fed through an inlet hopper 10 into the inlet or front end of the drum, and is delivered from an outlet or discharge orifice 11 in the rear end of the drum.- The arrangement of this con veyer is such that the material is slowlycarried from the'inlet end of the drum to the discharge end thereof. The teeth or blades of this conveyerclosely approach-the periphery of the drum so as to scrape off any material which may have a tendency to lodge on the'wall of the drum. ,This conveyer also'tendsto agitate and eomminute or still further break up the material sothat it will be more uniformly exposed to the heat of" the non-oxidizing agent, to-wit, the superheated steam. By means'of this combined agitator and conveyer the material will be more effectively. exposed to the action-of the heat. 7 Preferably the steam is taken out of the retort by means of an exhaust fan 12 connected by a pipe 13 to the drum at per 10.

the base of the hop- Incertain instances it may be desirable to close up the inlet and .discharge orifices of the retort. Accordingly, the hopper is provided with a weighted damper 14 of well known construction. This damper is so arranged that the inlet-passage is closed except when the Weight of the material freshly charged is forced into it. It also should be arranged so that the-orifice of the inlet passage of the hopper may be constric'ted.

The discharge passage is controlled by a. damper 15. A cut off valve 16 maybe interposed in the pipe 13 if desired.

By closing the valve 13 and dampers 14.

and 15 the non-oxidizingagent may be introduced into the retort and the-material treated under pressure. A valve 17 may be interposed in the discharge branch 5 and a check-valve 18 in inlet pipe l leading from the boiler. The furnace is provided with a suitable chimney-19f 1 I This process may also be utilized for softening rock asphalts, and the like, natural bituminous compositions, mastics, and special bituminous compositions in which the filler may consist of cork, woody matters, and materials of like nature.

I claim as my invention: 1. A process of treating old or used bituminous pavements which consists in breaking the pavement up 'into relatively small particles, agitating and further comminuting said material from the inlet end to the discharge end of said retort, feeding fresh material to said retort, and during said operations subjecting said material to the 'action of blasts of highly superheated steam and heating the bituminous binder above its melting point, and continuing the treatment until the binder is softened but without injury to the binder.-'

' 2. A process of treating bituminous compositions which consists in breaking up said composition into relatively small particles,

subjecting it to the action of highly super- .heated steam at temperatures above400? F.,

and continuing the process until the composition is softened without injury to the binder so that it may be reused or mixed with fresh bitumens. i I

4. A process'ofv treating'bituminous compositions composed of a non-bituminous ag- .ing'said material in a suitable retort, movgregate and a bituminous binder, which consists in heating said material in a suitable receptacle and introducing into said receptacle highly superheated steam and maintaining a pressure above atmospheric on the contents of said receptacle during said treatmenta 5. The process of treating bituminous compositions composed of a non-bituminous aggregate and a bituminous binder which consists in subjecting the same to the action of heat in a suitable receptacle which is externally heated by the action of steam and also passing superheated steam through said receptacle and continuing the process until the composition is softened Without injury to the binder so that it may be reused.

6. A process of treating'bituminous compositions composed of a non-bituminous aggregate and a bituminous binder which comsists in subjecting said compositions in a suitable receptacle to heat produced by passing super-heated steam through said recepcomposition is softened, and thus permitting the composition to be re-used.

7. The process of treating bituminous compositions composed of a non-bituminous aggregate and a bituminous binder which consists in subjecting said compositions. in a receptacle to the action of heat produced partially by passing superheated steam through the receptacle and partially 'by 'heating the receptacle externally with jacketed steam interposed between the receptacle and a suitable fire-box.

LESTER KIRSCHBRAUN. Witnesses J OYCE M. Lo'rz, C. B. BELKNAP.

, tacle, whereby the bituminous binder of said I 

